The disclosure relates to a hydrostatic axial piston machine having a pot-like housing which has a housing base and a housing jacket, having a connection plate, which closes the pot-like housing at its open side, having a rotatably mounted cylinder drum which is located in an interior formed by the housing and the connection plate and has a plurality of cylinder chambers in which pistons executing a stroke movement during operation are arranged. During operation, each cylinder chamber is alternately connected, via a cylinder chamber opening, to a low-pressure control opening and a high-pressure control opening of a resting control part. At this control part, two switching regions, within which a piston reverses its movement direction in a dead center, are located between the low-pressure control opening and the high-pressure control opening. In the switching region, after leaving one control opening and still prior to reaching the other control opening, the cylinder chambers are connected via a connecting line to a fluid volume arranged in the housing. It is thus possible for sudden changes in pressure in the cylinder chambers to be prevented so that the load on the components, pressure pulsations and the noise emissions associated with rapid variations in pressure are reduced.
Since the cylinder chambers are predominantly connected to the fluid volumes when switching from low pressure to high pressure and a pre-compression of the fluid located in a cylinder chamber thereby takes place, the fluid volume is generally also referred to as a pre-compression volume. If the cylinder chambers are connected to a fluid volume when switching from high pressure to low pressure, then this is, strictly speaking, a pre-decompression volume. However, this expression is not used below.
The terms fluid volume or pre-compression volume are used below to refer to a cavity which is filled, or is to be filled, with a liquid pressurizing medium, for example with hydraulic oil, and in which a variation in pressure is associated with an inflow or an outflow of pressurizing medium solely as a result of the compressibility of the pressurizing medium.
A hydrostatic axial piston machine is disclosed in DE 10 2013 226 344 A1. According to this document, the fluid volume is formed as an interior of a bottle-like separate hollow body which is fastened by its neck in a bore of the connection plate. The advantage of this solution is the high reliability against leakage into the environment since there is no interface to the outside of the housing. In the event of a leak between the hollow body and the connection plate, the leakage oil flowing into the interior merely increases. The disadvantage is that the bottle-like hollow body is difficult to produce. Moreover, the manner in which the hollow body is fastened in the connection plate has to withstand the forces seeking to push the hollow body out of the bore.
A hydrostatic axial piston machine having a pre-compression volume is also disclosed in DE 10 2014 223 492 A1. According to this document, the fluid volume is formed as a cavity in the connection plate, which is closed to the interior by a plug. It is also advantageous here that leakage between the connection plate and the plug only takes place into the interior. However, there is only a small amount of space available in the connection plate for a pre-compression volume.
A hydrostatic axial piston machine having a pre-compression volume is also disclosed in DE 10 2014 223 489 A1. According to this document, the fluid volume is a cavity which is formed by the housing and the connection plate. An embodiment is shown in which the cavity is composed of a sub-chamber in a flange face of the connection plate, which flange face faces the housing, and a sub-chamber in a flange face of the housing, which flange face faces the connection plate. There is the possibility here of an outward leakage into the environment.
The object of the disclosure is to design a hydrostatic axial piston machine having the features of the disclosure such that the fluid volume is realized in a simple and economical manner.